Thermoelectric device having a polymeric coating

ABSTRACT

A method of fabricating a thermoelectric device includes providing a thermoelectric device having a thermally conductive first plate, a thermally conductive second plate, and a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate. The plurality of thermoelectric elements is in thermal communication with the first plate and the second plate. The method further includes forming a polymeric coating in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are incorporated by reference and made a part of this specification.

BACKGROUND Field

This application relates to thermoelectric devices and modules used for thermal management of components and/or systems, including but not limited to batteries.

Description of the Related Art

Power electronics and other electrical devices, such as batteries, can be sensitive to overheating, cold temperatures, extreme temperatures, and operating temperature limits. The performance of such devices may be diminished, sometimes severely, when the devices are operated outside of recommended temperature ranges. In semiconductor devices, integrated circuit dies can overheat and malfunction. In batteries, including, for example, batteries used for automotive applications in electrified or electrical vehicles, battery cells and their components can degrade when overheated or overcooled. Such degradation can manifest itself in reduced battery storage capacity and/or reduced ability for the battery to be recharged over multiple duty cycles. Furthermore, high performance batteries for use in large systems (including, for example, lithium based batteries used in electrical vehicles) have certain properties (e.g., charging characteristics) and/or safety-related events (e.g., potential fires due to over-temperature conditions) that make thermal management of the batteries and/or containment system desirable.

SUMMARY

In certain embodiments, a method of fabricating a thermoelectric device is provided. The method comprises providing a thermoelectric device comprising a thermally conductive first plate, a thermally conductive second plate, and a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate. The plurality of thermoelectric elements is in thermal communication with the first plate and the second plate. The method further comprises forming a polymeric coating in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements.

In certain embodiments, a thermoelectric device is provided. The thermoelectric device comprises a thermally conductive first plate and at least one thermoelectric sub-assembly. The at least one thermoelectric sub-assembly comprises a thermally conductive second plate, a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate, the plurality of thermoelectric elements in thermal communication with the first plate and the second plate, and a hermetic seal comprising at least one polymeric material in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements.

In certain embodiments, a thermoelectric module for thermally conditioning a component is provided. The module comprises first and second heat spreaders spaced apart from one another and configured to respectively provide cold and hot sides. The module further comprises a thermal insulator material arranged between the first and second heat spreaders. The module further comprises a thermoelectric device operatively engaged with the first and second heat spreaders. The thermoelectric device comprises a thermally conductive first plate in thermal communication with the first heat spreader and a plurality of thermoelectric sub-assemblies. Each thermoelectric sub-assembly comprises a thermally conductive second plate in thermal communication with the second heat spreader and having a plurality of edges, a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate, and at least one hermetic seal. The plurality of thermoelectric elements is in thermal communication with the first plate and the second plate. The at least one hermetic seal comprises at least one polymeric material in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically illustrates a top view of an example thermoelectric device in accordance with certain embodiments described herein.

FIG. 1B schematically illustrates a cross-sectional view of the example thermoelectric device of FIG. 1A.

FIG. 2A schematically illustrates a top view of another example thermoelectric device in accordance with certain embodiments described herein.

FIGS. 2B and 2C schematically illustrate two cross-sectional views in two different planes of the example thermoelectric device of FIG. 2A.

FIGS. 3A and 3B schematically illustrate a perspective view and an exploded view, respectively, of an example thermoelectric device comprising four thermoelectric sub-assemblies in accordance with certain embodiments described herein.

FIGS. 4A-4J schematically illustrate portions of various example thermoelectric devices with the at least one material along various portions of the perimeter of the one or more thermoelectric assemblies in accordance with certain embodiments described herein.

FIG. 5 schematically illustrates a thermoelectric module for thermally conditioning a component in accordance with certain embodiments described herein.

FIG. 6 is a flow diagram of an example method of fabricating a thermoelectric device in accordance with certain embodiments described herein.

DETAILED DESCRIPTION

FIG. 1A schematically illustrates a top view of an example thermoelectric device 100 in accordance with certain embodiments described herein. FIG. 1B schematically illustrates a cross-sectional view of the example thermoelectric device 100 of FIG. 1A.

The thermoelectric device 100 of FIGS. 1A-1B comprises a thermally conductive first plate 110 and at least one thermoelectric sub-assembly 114 comprising a thermally conductive second plate 120, a plurality of thermoelectric (“TE”) elements 130, and a hermetic seal 140. The plurality of TE elements 130 is in a region 132 bounded by and including (e.g., between) the first plate 110 and the second plate 120 and is in thermal communication with the first plate 110 and the second plate 120. The hermetic seal 140 comprises at least one polymeric material 142 in the region 132 on at least one surface 118 of the first plate 110, at least one surface 128 of the second plate 120, and at least one surface 138 of the plurality of TE elements 130.

In certain embodiments, each of the first plate 110 and the second plate 120 comprises a planar laminate structure (e.g., a printed circuit board or PCB) having one or more electrically conductive layers (e.g., copper; aluminum; metal; metal alloy or composite) and one or more electrically insulating layers (e.g., fiberglass; resin; polymer; fibrous material preimpregnated with a resin material such as epoxy). The one or more electrically conductive layers can be configured to provide electrical connections to the plurality of TE elements 130. For example, an outer electrically conductive layer of the one or more electrically conductive layers of the first plate 110 can comprise electrically conductive pads on the at least one surface 118 of the first plate 110 in the region 132 which are configured to be coupled (e.g., soldered) to the TE elements 130, and the pads can be in electrical communication with other pads of the first plate 110 (e.g., by electrically conductive lines formed by selective chemical etching of the electrically conductive layers and by electrically conductive vias formed through the electrically insulating layers). Similarly, an outer electrically conductive layer of the one or more electrically conductive layers of the second plate 120 can comprise electrically conductive pads on the at least one surface 128 of the second plate 120 in the region 132 which are configured to be coupled (e.g., soldered) to the TE elements 130, and the pads can be in electrical communication with other pads of the second plate 120 (e.g., by electrically conductive lines formed by selective chemical etching of the electrically conductive layers and by electrically conductive vias formed through the electrically insulating layers).

In certain embodiments, the first plate 110 has a planar parallelogram shape (e.g., rhombus shape; rectangular shape; square shape) with four edges 116 (e.g., a rectangular shape with two shorter edges and two longer edges). The first plate 110 can have other planar shapes (e.g., polygonal) with other numbers of edges 116 in accordance with certain embodiments described herein (e.g., triangular shapes with three edges; trapezoidal shapes with four edges; pentagonal shapes with five edges; hexagonal shapes with six edges; etc.). In certain embodiments, the second plate 120 has a planar parallelogram shape (e.g., rhombus shape; rectangular shape; square shape) with four edges 126 (e.g., a rectangular shape with two shorter edges and two longer edges). The second plate 120 can have other planar shapes (e.g., polygonal) with other numbers of edges 126 in accordance with certain embodiments described herein (e.g., triangular shapes with three edges; trapezoidal shapes with four edges; pentagonal shapes with five edges; hexagonal shapes with six edges; etc.).

In certain embodiments, the plurality of TE elements 130 comprises p-type TE elements and n-type TE elements in electrical communication with one another through a plurality of shunts (e.g., electrically conductive pads of the first plate 110 and the second plate 120). For example, the plurality of TE elements 130 can be arranged in a “stonehenge” configuration in which p-type and n-type TE elements alternate with one another and are in series electrical communication with one another by shunts which are alternately positioned on the first plate 110 and the second plate 120 such that electrical current can flow serially through the TE elements 130 and the shunts in a serpentine fashion. The TE elements have a plurality of surfaces 138 in the region 132. In certain embodiments, the plurality of TE elements 130 are in thermal communication with the first plate 110 through the shunts (e.g., electrically conductive pads) on the at least one surface 118 of the first plate 110 and in thermal communication with the second plate 120 through the shunts (e.g., electrically conductive pads) on the at least one surface 128 of the second plate 120. In certain embodiments, the region 132 containing the plurality of TE elements 130 is bounded by and includes (e.g., between) the first plate 110 and the second plate 120 and has a perimeter 134 defined by the second plate 120 (e.g., the perimeter 134 is coincident with the plurality of edges 126 of the second plate 120).

In certain embodiments, a top surface of the first plate 110 (e.g., a surface of the first plate 110 closest to the second plate 120) has a first surface area and a top surface of the second plate 120 (e.g., a surface of the second plate 120 farthest from the first plate 110) has a second surface area less than the first surface area. For example, the thermoelectric device 100 can comprise a plurality of thermoelectric sub-assemblies 114, each comprising a corresponding second plate 120 and a corresponding plurality of TE elements 130 (e.g., the plurality of second plates 120 are mounted to a common first plate 110), and the first plate 110 can have a surface area larger than the sum of the surface areas of the second plates 120.

In certain embodiments, the first plate 110 and the second plate 120 are spaced from one another by a gap having a gap height. For example, the gap between the top surface of the first plate 110 and a bottom surface of the second plate 120 (e.g., a surface of the second plate 120 closest to the first plate 110) can be in a range between 0.4 millimeter and 3 millimeters. In certain such embodiments, the second plate 120 has a planar polygonal shape with a plurality of edges 126 (e.g., a rectangular shape with two opposing edges each having a first length and two opposing edges each having a second length less than the first length), and the second plate 120 has a plate width between opposing edges of the plurality of edges 126 (e.g., the plate width equal to the second length). The ratio of the gap height to the plate width can be in a range between 1:20 and 1:30.

In certain embodiments, the at least one polymeric material 142 of the hermetic seal 140 comprises poly(para-xylylene) polymers (e.g., parylene). Other example polymeric materials compatible with certain embodiments described herein include but are not limited to: silicone; epoxy. In the example thermoelectric device 100 of FIG. 1B, the at least one polymeric material 142 comprises one or more layers on multiple portions of the top surface of the first plate 110 (e.g., portions of the surface 118 within the region 132), on multiple portions of the bottom surface of the second plate 120 (e.g., portions of the surface 128 within the region 132), and multiple portions of the surfaces of the TE elements 130 (e.g., portions of the surfaces 138 within the region 132). For example, the at least one polymeric material 142 can have a thickness in a range between 0.5 micron and 3 microns on surfaces coated by the at least one polymeric material 142.

While FIG. 1B schematically illustrates an example in which all the surfaces within the region 132 are coated with the at least one polymeric material 142, in certain other embodiments, some portions of the surfaces within the region 132 are coated with the at least one polymeric material 142 while other portions of the surfaces within the region 132 are not coated with the at least one polymeric material 142. For example, an outer portion of the region 132 (e.g., a portion of the region 132 adjoining the perimeter 134 of the region 132) can be coated by the at least one polymeric material 142 while an inner portion of the region 132 (e.g., a portion of the region not adjoining the perimeter 134 of the region 132) is not coated by the at least one polymeric material 142. While FIG. 1B schematically illustrates an example in which the region 132 contains voids between the first plate 110, second plate 120, and TE elements 130 which are not filled by the at least one polymeric material 142, in certain other embodiments, the at least one polymeric material 142 substantially fills the region 132.

In certain embodiments, the at least one polymeric material 142 coats one or more surfaces outside of the region 132. For example, the at least one polymeric material 142 can coat one or more of the following: at least a portion of a first surface of the first plate 110 (e.g., at least a portion of a bottom surface of the first plate 110; at least a portion of the surface on an opposite side of the first plate 110 from the thermoelectric sub-assembly 114; at least a portion of a surface configured to be in thermal communication with a first heat spreader; at least a portion of the top surface of the first plate 110 spaced laterally away from the region 132; at least a portion of the surface on the same side of the first plate 110 as the thermoelectric sub-assembly 114 but spaced laterally away from the thermoelectric sub-assembly 114), at least a portion of a surface of one or more electrical components (e.g., wire connections) coupled to one of the first plate 110 and the second plate 120, and at least a portion of a second surface of the second plate 120 (e.g., at least a portion of a top surface of the second plate 120; at least a portion of the surface on an opposite side of the second plate 120 from the TE elements 130; at least a portion of a surface configured to be in thermal communication with a second heat spreader).

FIG. 2A schematically illustrates a top view of another example thermoelectric device 100 in accordance with certain embodiments described herein. FIGS. 2B and 2C schematically illustrate two cross-sectional views in two different planes of the example thermoelectric device 100 of FIG. 2A. As schematically illustrated by FIGS. 2A-2C, in certain embodiments, the at least one thermoelectric sub-assembly 114 further comprises at least one material 144 (e.g., epoxy; rubber; silicone) along at least a portion 146 of the perimeter 134 of the region 132 and mechanically coupled to the first plate 110 and the second plate 120. In certain such embodiments, the hermetic seal 140 comprises the at least one material 144 and the at least one polymeric material 142. For example, the at least one material 144 can be mechanically coupled to the first plate 110 and the second plate 120 around at least a portion of an edge 126 of the second plate 120, and the polymeric material 142 can form a remaining portion of the hermetic seal 140.

In certain embodiments, the first plate 110 comprises at least one hole 112 configured to have at least one fastener extend through the at least one hole 112. As described more fully herein, the thermoelectric device 100 and the at least one fastener (e.g., bolt; screw; pin; rivet) are components of a thermoelectric module in which the thermoelectric device 100 is sandwiched between and in thermal communication with first and second heat spreaders that are mechanically coupled together by the at least one fastener. The shape of the at least one hole 112 can be circular, as schematically illustrated in FIG. 2A, or non-circular (e.g., rectangular). In certain embodiments, the at least one hole 112 and the at least one thermoelectric sub-assembly 114 are displaced (e.g., located away) from one another in the direction 122 parallel to the first plate 110 (e.g., laterally displaced from one another). For example, as schematically shown in FIGS. 2A and 2B, the direction 122 extends along the first plate 110 and an edge 113 of the at least one hole 112 is spaced away from the at least one thermoelectric sub-assembly 114 (e.g., spaced away from the second plate 120) in the direction 122. In certain such embodiments, the second plate 120 of the thermoelectric sub-assembly 114 does not extend over or around the at least one hole 112.

FIGS. 3A and 3B schematically illustrate a perspective view and an exploded view, respectively, of an example thermoelectric device 100 comprising four thermoelectric sub-assemblies 114 in accordance with certain embodiments described herein. In FIGS. 3A and 3B, the thermoelectric device 100 comprises a first plate 110 (e.g., PCB) having a rectangular shape with four edges 116 (e.g., two shorter edges 116 a and two longer edges 116 b). The first plate 110 comprises a plurality of holes 112 (e.g., configured to mount the thermoelectric device 100 within a thermoelectric module) and a plurality of electrically conductive shunts 210 (e.g., solder pads) configured to be in electrical communication and thermal communication with the TE elements 130 of the four thermoelectric sub-assemblies 114. Each of the four thermoelectric sub-assemblies 114 of FIGS. 3A and 3B comprises a plurality of TE elements 130, and a second plate 120 having a rectangular shape with four edges 126 (e.g., two shorter edges 126 a and two longer edges 126 b) and having a plurality of electrically conductive shunts (not shown) (e.g., solder pads) configured to be in electrical and thermal communication with the plurality of TE elements 130. FIG. 3A also shows a pair of electrical conductors (e.g., wires) configured to be in electrical communication with electrically conductive pads (e.g., solder pads) of the first plate 110 and to transmit electrical power to and/or from the thermoelectric sub-assemblies 114. FIGS. 3A and 3B do not show the at least one polymeric material 142 or the at least one material 144, but various configurations of the at least one polymeric material 142 or the at least one material 144 are compatible to be used with the thermoelectric device 100 of FIGS. 3A and 3B in accordance with certain embodiments are described herein.

The thermoelectric sub-assemblies 114 of FIGS. 3A and 3B are substantially equally spaced from one another (e.g., within ±5%; within ±1%) across the first plate 110 with a pair of holes 112 between the longer edges 126 b of the second plates 120 of adjacent thermoelectric sub-assemblies 114. The edges 113 of the holes 112 of FIGS. 3A and 3B are displaced from the longer edges 126 b of the second plates 120 (e.g., along a direction 122 parallel to the first plate 110; along a direction perpendicular to the longer edge 126 b and to the edge 113). In certain other embodiments, the thermoelectric sub-assemblies 114 are not substantially equally spaced from one another, and/or the number of holes 112 between the adjacent thermoelectric sub-assemblies 114 is not equal to two (e.g., one; more than two).

The two shorter edges 126 a of the second plates 120 of each of the thermoelectric sub-assemblies 114 of FIGS. 3A and 3B are aligned (e.g., flush) with longer edges 116 b of the first plate 110, and the two thermoelectric sub-assemblies 114 at opposite ends of the thermoelectric device 100 have one of the longer edges 126 b of the second plate 120 aligned (e.g., flush) with a respective shorter edge 116 a of the first plate 110. In certain other embodiments, other edges 116 of the first plate 110 and other edges 126 of the second plate 120 can be aligned (e.g., flush) with one another or can extend past one another.

In certain embodiments, as schematically illustrated by FIGS. 2A-2C, the at least one material 144 (e.g., epoxy; rubber; silicone) extends along at least a portion 146 of the perimeter 134 of the region 132 and is in mechanical communication with the first plate 110 and the second plate 120. For example, the first plate 110 can comprise a first plurality of edges 116 and the second plate 120 can comprise a second plurality of edges 126, with the first plurality of edges 116 extending beyond the second plurality of edges 126, as schematically shown in FIG. 2A. The portion of the first plate 110 extending beyond the second plurality of edges 126 (e.g., the portion between the edge 116 and the nearest edge 126) can provide sufficient area to be mechanically coupled to the at least one material 144. As shown in FIGS. 2B and 2C, the at least one material 144 can be mechanically coupled to the top surface of the first plate 110 and to an edge 126 of the second plate 120. In certain other embodiments, at least some of the edges 126 of the second plates 120 are aligned (e.g., flush) with one or more edges 116 of the first plate 110, and the at least one material 144 can be mechanically coupled to the aligned edges 116, 126 without one of the first plate 110 and the second plate 120 extending past the other in a direction generally parallel to the first plate 110 and/or the second plate 120. The at least one material 144 of certain embodiments comprises at least a first material (e.g., epoxy; rubber; silicone) extending along a first portion of the perimeter 134 and a second material (e.g., epoxy; rubber; silicone) extending along a second portion of the perimeter 134.

In certain embodiments, the hermetic seal 140 comprises the at least one polymeric material 142 and the at least one material 144. For example, the at least one polymeric material 142 at least partially overlaps (e.g., extends over) the at least one material 144 or the at least one material 144 at least partially overlaps (e.g., extends over) the at least one polymeric material 142 to form a continuous hermetic seal 140 around the TE elements 130 and other surfaces within the region 132. In certain such embodiments, there are no gaps between the at least one polymeric material 142 and the at least one material 144.

In certain embodiments, the at least one material 144 is selected to provide additional stiffness to portions of the thermoelectric sub-assembly 114 which are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). FIGS. 4A-4J schematically illustrate portions of various example thermoelectric devices 100 with the at least one material 144 along various portions 146 of the perimeter 134 of the one or more thermoelectric assemblies 114 in accordance with certain embodiments described herein. While FIGS. 4A-4J show the at least one material 144 comprising a single material (e.g., epoxy; rubber; silicone) extending along the portions 146, in certain embodiments, the at least one material 144 further comprises one or more additional materials (e.g., silicone) along remaining portions of the perimeter 134 and in mechanical communication with the first plate 110 and the second plate 120, the one or more additional materials less stiff than the single material schematically shown in FIGS. 4A-4J.

In each of FIGS. 4A-4J, the one or more second plates 120 are displaced (e.g., laterally displaced; spaced away) from the adjacent one or more holes 112 (e.g., the second plates 120 do not extend over or around the one or more holes 112). While the second plates 120 schematically shown in FIGS. 4A-4J are rectangular with two longer edges and two shorter edges each, other embodiments have other planar shapes with other numbers of edges. In addition, while the second plates 120 schematically shown in FIGS. 4A-4J have their shorter edges adjacent to two opposite edges 116 of the first plate 110, other embodiments have the second plates 120 at other positions and/or orientations relative to the edges 116 of the first plate 110. Various combinations of the thermoelectric sub-assemblies 114 and the portions 146 schematically shown in FIGS. 4A-4J are also compatible with certain embodiments described herein.

FIGS. 4A-4C schematically illustrate portions of various example thermoelectric devices 100 comprising at least two thermoelectric sub-assemblies 114 each having a second plate 120 with a hole 112 of the first plate 110 therebetween in accordance with certain embodiments described herein. FIGS. 4A-4C are compatible with certain embodiments in which the portions of the thermoelectric sub-assemblies 114 closest to the hole 112 are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). In FIG. 4A, the at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the hole 112 and the portion 146 extends along a length of the perimeter 134 that is substantially equal (e.g., within ±5%; within ±1%) to a width (e.g., the diameter) of the hole 112 (indicated by the dashed lines). In FIG. 4B, the at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the hole 112 and the portion 146 extends along a length of the perimeter 134 that is greater than a width (e.g., the diameter) of the hole 112 (indicated by the dashed lines). For example, the length of the portion 146 can be between 5% and 10% greater than the width; between 10% and 20% greater than the width; between 20% and 100% greater than the width; between 50% and 150% greater than the width. In certain other embodiments, the at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the hole 112 and the portion 146 extends along a length of the perimeter 134 that is less than a width (e.g., the diameter) of the hole 112 (e.g., between 2% and 10% less than the width; between 10% and 20% less than the width; between 20% and 50% less than the width). In FIG. 4C, the at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the hole 112 and the portion 146 extends along a length of the perimeter 134 that is substantially equal (e.g., within ±5%; within ±1%) of the longer edge 126 b of the second plate 120.

FIG. 4D schematically illustrates a portion of another example thermoelectric device 100 comprising a hole 112 of the first plate 110 positioned between a thermoelectric sub-assembly 114 and an edge 116 of the first plate 110 in accordance with certain embodiments described herein. FIG. 4D is compatible with certain embodiments in which the portions of the thermoelectric sub-assemblies 114 closest to the hole 112 are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). The at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the hole 112 and the portion 146 extends along a length of the perimeter 134 that is substantially equal (e.g., within ±5%; within ±1%) to a width (e.g., the diameter) of the hole 112 (indicated by the dashed lines), that is greater than the width (e.g., between 5% and 10% greater than the width; between 10% and 20% greater than the width; between 20% and 100% greater than the width; between 50% and 150% greater than the width), that is less than the width (e.g., between 2% and 10% less than the width; between 10% and 20% less than the width; between 20% and 50% less than the width), or that is substantially equal (e.g., within ±5%; within ±1%) to the longer edge 126 b of the second plate 120 (e.g., the full length of the exterior edge of the second plate 120).

FIGS. 4E-4F schematically illustrate portions of various example thermoelectric devices 100 comprising at least two thermoelectric sub-assemblies 114 each having a second plate 120 with two holes 112 of the first plate 110 therebetween in accordance with certain embodiments described herein. FIGS. 4E-4F are compatible with certain embodiments in which the portions of the thermoelectric sub-assemblies 114 closest to the holes 112 are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). In FIG. 4E, the at least one material 144 extends along multiple sub-portions 146 of the perimeter 134 that are each closest to a corresponding one of the two holes 112. For example, the multiple portions 146 of FIG. 4E comprise two sub-portions separated from one another. Each of the sub-portions 146 in FIG. 4E extends along a length of the perimeter 134 that is substantially equal (e.g., within ±5%; within ±1%) to a width (e.g., the diameter) of the corresponding hole 112 (indicated by the dashed lines). In certain other embodiments, each of the sub-portions 146 extends along a length of the perimeter 134 adjacent to the corresponding hole 112 with the length greater than the width (e.g., between 5% and 10% greater than the width; between 10% and 20% greater than the width; between 20% and 100% greater than the width; between 50% and 150% greater than the width) or that is less than the width (e.g., between 2% and 10% less than the width; between 10% and 20% less than the width; between 20% and 50% less than the width) of the corresponding hole 112 (indicated by the dashed lines). In FIG. 4F, the at least one material 144 extends along a portion 146 of the perimeter 134 that is closest to the two holes 112 and that extends along a length of the perimeter 134 that is greater than a width (e.g., the diameter) of either of the two holes 112 (indicated by the dashed lines) including a sub-portion between the two holes 112. In certain embodiments, the portion 146 extends along a length of the perimeter 134 that is substantially equal (e.g., within ±5%; within ±1%) of the longer edge 126 b of the second plate 120.

FIGS. 4G and 4H schematically illustrate portions of example thermoelectric devices 100 in which the at least one material 144 extends along a portion 146 of the perimeter 134 that extends along a full length of one or more longer edges of the second plates 120 in accordance with certain embodiments described herein. The two longer edges 126 b of the two second plates 120 facing away from the thermoelectric device 100 can be referred to as “exterior” edges (e.g., the longer edges 126 b of the second plates 120 that are adjacent to a shorter edge 116 a of the first plate 110). FIGS. 4G-4H are compatible with certain embodiments in which the exterior edges of the second plates 120 are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). In FIG. 4G, one of the two thermoelectric sub-assemblies 114 has an exterior edge (e.g., a longer edge of a second plate 120 facing away from the other thermoelectric sub-assemblies 114 of the thermoelectric device 100; a longer edge of a second plate 120 adjacent to a shorter edge of the first plate 110) and the portion 146 extends along a full length of the exterior edge. In FIG. 4H, two thermoelectric sub-assemblies 114 each have an exterior edge and the portion 146 extends along a full length of each of the exterior edges.

FIGS. 4I and 4J schematically illustrated portions of thermoelectric devices 100 in which the at least one material 144 extends along portions 146 of the perimeter 134 that extend along at least one corner of the second plates 120 in accordance with certain embodiments described herein. FIGS. 4I-4J are compatible with certain embodiments in which the portions of the thermoelectric sub-assemblies 114 around at least some of the corners of the second plates 120 are expected to experience higher mechanical stresses, pressures, and/or forces than other portions (e.g., during assembly and/or operation of a thermoelectric module comprising the thermoelectric device 100). In FIG. 4I, the portions 146 extend along (e.g., around) the corners of an exterior edge of the second plate 120 (e.g., the corners farthest from the at least one hole 112). In FIG. 4J, the portions 146 extend along (e.g., around) the corners of an interior edge of the second plate 120 (e.g., the corners closest to the at least one hole 112; the corners of the two longer edges 126 b of the two adjacent second plates 120 that face one another; the corners of the two longer edges 126 b of the second plates 120 with two holes 112 between them and that are not adjacent to a shorter edge 116 a of the first plate 110). While FIGS. 4I and 4J show the portions 146 extending along two corners of each second plate 120, certain other embodiments have the portions 146 extending along different numbers of corners of the second plate 120 (e.g., one; more than two).

FIG. 5 schematically illustrates a thermoelectric module 400 for thermally conditioning a component (e.g., an electronics component; a battery) in accordance with certain embodiments described herein. The module 400 comprises a first heat spreader 410 and a second heat spreader 420 spaced apart from one another and configured to respectively provide cold and hot sides. The module 400 further comprises a thermal insulator material 430 arranged between the first heat spreader 410 and the second heat spreader 420. The module 400 further comprises a thermoelectric device 100 operatively engaged with the first heat spreader 410 and the second heat spreader 420. In certain embodiments, the first heat spreader 410 and the second heat spreader 420 are configured to be mechanically coupled together by at least one fastener (e.g., bolt; screw; pin; rivet) (not shown).

The thermoelectric device 100 comprises a thermally conductive first plate 110 in thermal communication with the first heat spreader 410 and a plurality of thermoelectric sub-assemblies 114. For example, the first plate 110 can comprise at least one hole 112 configured to have the at least one fastener extend therethrough and the plurality of thermoelectric sub-assemblies 114 can be arranged to have the at least one fastener between adjacent thermoelectric sub-assemblies 114 (see, e.g., FIG. 5).

Each thermoelectric sub-assembly 114 comprises a thermally conductive second plate 120 in thermal communication with the second heat spreader 420 and having a plurality of edges 126, and a plurality of TE elements 130 in a region 132 bounded by and including (e.g., between) the first plate 110 and the second plate 120 and in thermal communication with the first plate 110 and the second plate 120. Each thermoelectric sub-assembly 114 further comprises at least one hermetic seal 140 comprising at least one polymeric material 142 in the region 132 on at least one surface 118 of the first plate 110, at least one surface 128 of the second plate 120, and at least one surface 138 of the plurality of TE elements 130. FIGS. 1A-1B, 2A-2C, 3A-3B, and 4A-4J schematically illustrate various example thermoelectric devices 100 and thermoelectric sub-assemblies 114 in accordance with certain embodiments described herein. For example, the at least one polymeric material 142 can comprise poly(para-xylylene) polymers.

In certain embodiments, the first heat spreader 410 and the second heat spreader 420 are configured to transfer heat away from the component to be thermally conditioned. For example, as schematically illustrated by FIG. 5, the first heat spreader 410 can be configured to transfer heat to the thermoelectric device 100 from the component to be thermally conditioned, and the second heat spreader 420 can be configured to transfer heat away from the thermoelectric device 100. The first heat spreader 410 can comprise at least one first surface 412 configured to be in thermal communication with the thermoelectric device 100 and at least one second surface 414 configured to be in thermal communication with the component to be thermally conditioned by the module 400, and the second heat spreader 420 can comprise at least one first surface 422 configured to be in thermal communication with the thermoelectric device 100. For example, at least one second surface 424 of the second heat spreader 420 can comprise at least one heat dissipation structure (e.g., at least one fin) configured to transfer heat from the second heat spreader 420 to the ambient surroundings. For another example, the second heat spreader 420 can be configured to have a fluid coolant (e.g., liquid; air; refrigerant) flow therethrough. While FIG. 5 schematically illustrates an example thermoelectric module 400 in which the first heat spreader 410 provides at least one cold side that receives heat from the component to be thermally conditioned and in which the second heat spreader 420 provides at least one hot side that serves as a heat sink which receives heat from the thermoelectric device 100, in certain other embodiments, the second heat spreader 420 provides the at least one cold side and the first heat spreader 410 provides the at least one hot side.

In certain embodiments, the thermal insulation material 430 comprises a compressible material (e.g., polymer; plastic; rubber; fiberglass) and is configured to be at least partially compressed by the first heat spreader 410 and the second heat spreader 420 during assembly of the thermoelectric module 400 while keeping the first heat spreader 410 and the second heat spreader 420 from contacting one another. In certain embodiments, the thermal insulation material 430 generally surrounds the thermoelectric device 100 (e.g., as shown in FIG. 5), and comprises conduits (e.g., holes; recesses; cut-out portions) (not shown) configured to accommodate one or more electrical conduits (e.g., wires) in electrical communication with the thermoelectric device 100 by allowing the one or more electrical conduits to extend from the thermoelectric device 100 to outside the thermoelectric module 400. In certain embodiments in which the thermoelectric device 100 comprises a plurality of thermoelectric sub-assemblies 114, the thermal insulation material 430 does not extend between the thermoelectric sub-assemblies 114. In certain embodiments, the insulation material 430 provides hermetic sealing and/or a moisture barrier for the volume occupied by the thermoelectric device 100.

In certain embodiments, during operation and/or assembly of the thermoelectric module 400, the portion 146 of the plurality of edges 126 experiences a first mechanical force, pressure, and/or stress from the second heat spreader 420 and a remaining portion of the plurality of edges 126 experiences a second mechanical force, pressure, and/or stress from the second heat spreader 420, with the second mechanical force, pressure, and/or stress less than the first mechanical force, pressure, and/or stress. By having the at least one material 144 (e.g., epoxy; rubber; silicone) with its stiffness along portions of the thermoelectric sub-assemblies 114 where the mechanical force and/or stress from the second heat spreader 420 are expected to be higher than along other portions, certain embodiments described herein advantageously provide enhanced durability and reliability of the thermoelectric device 100 and the thermoelectric module 400 (e.g., during assembly and/or operation of the thermoelectric module 400).

The at least one polymeric material 142 of certain embodiments advantageously provides an electrically insulating coating and/or a corrosion-resistant coating on various portions of the first plate 110, the second plate 120, and/or one or more electrical components (e.g., wire connections) coupled to one of the first plate 110 and the second plate 120. For example, within the region 132 and on surfaces of the plurality of TE elements 130, the polymeric material 144 can form a coating that is sufficiently thin (e.g., in a range between 0.5 micron and 3 microns) such that the polymeric material 144 does not substantially enhance the thermal conductivity between the first plate 110 and the second plate 120 within the region 132.

For another example, the polymeric material 144 can form a polymeric coating on the bottom surface of the first plate 110 and/or the top surface of the second plate 120. The polymeric coating on the first plate 110 can have sufficient thickness (e.g., in a range between 0.5 micron and 3 microns) to electrically insulate the first plate 110 from the first heat spreader 410 and/or to provide corrosion resistance of the first plate 110 (e.g., resistance to electro-corrosion between the first plate 110 and adjoining material of the first heat spreader 410), while maintaining a predetermined thermal conductivity between the first plate 110 and the first heat spreader 410. The polymeric coating on the top surface of the second plate 120 can have sufficient thickness (e.g., in a range between 0.5 micron and 3 microns) to electrically insulate the second plate 120 from the second heat spreader 420 and/or to provide corrosion resistance of the second plate 120 (e.g., resistance to electro-corrosion between the second plate 120 and adjoining material of the second heat spreader 420), while maintaining a predetermined thermal conductivity between the second plate 120 and the second heat spreader 420. In certain embodiments, the polymeric material 144 is configured to facilitate thermal conduction between the first plate 110 and the first heat spreader 410 and/or between the second plate 120 and the second heat spreader 420, thereby obviating the use of a separate graphite layer between the first plate 110 and the first heat spreader 410 and/or between the second plate 120 and the second heat spreader 420.

In certain embodiments, the thermoelectric module 400 comprises at least one seal (e.g., hermetic seal) at least partially surrounding a volume containing the thermoelectric elements 130 of the thermoelectric device 100. For example, the at least one seal can comprise at least a portion of the polymeric material 142 within the region 132, such that the first plate 110, second plate 120, and the polymeric material 142 seal a volume containing the thermoelectric elements 130. For another example, the at least one seal can comprise a material (e.g., epoxy; acrylic; polymer; rubber; silicone) between the first heat spreader 410 and the second heat spreader 420 and at least partially surrounding a volume containing the thermoelectric device 100 (e.g., potting a portion of the volume between the at least one first surface 412 of the first heat spreader 410 and the at least one first surface 422 of the second heat spreader 420. The material can be sufficiently rigid to provide mechanical strength to the thermoelectric module 400. In certain embodiments, additional material (e.g., epoxy; acrylic; polymer; rubber; silicone) is located and forms at least one seal between at least one screw head of the at least one fastener (not shown) and the at least one second surface 424 of the second heat spreader 420.

FIG. 6 is a flow diagram of an example method 600 of fabricating a thermoelectric device 100 in accordance with certain embodiments described herein. The example method 600 of certain embodiments can also be used for fabricating a thermoelectric module 400. While the method 600 is described by referring to the structures schematically illustrated in FIGS. 1A-1B, 2A-2C, 3A-3B, 4A-4J, and 5, the method 600 is also compatible with other structures.

In an operational block 610, a thermoelectric device is provided. The thermoelectric device comprises a thermally conductive first plate 110, a thermally conductive second plate 120, and a plurality of TE elements 130 in a region 132 bounded by and including (e.g., between) the first plate 110 and the second plate 120. The plurality of thermoelectric elements 130 are in thermal communication with the first plate 110 and the second plate 120. In an operational block 620, a polymeric coating (e.g., comprising at least one polymeric material 142) is formed in the region 132 on at least one surface of the first plate 110, at least one surface of the second plate 120, and at least one surface of the plurality of TE elements 130.

In certain embodiments, the method 600 further comprises applying at least one material 144 along at least a portion of a perimeter 134 of the region 132 such that the at least one material 144 is mechanically coupled to the first plate 110 and the second plate 120. For example, the at least one material 144 can be applied by extruding or spraying the at least one material 144 from at least one nozzle placed in proximity to the edges 126 of the second plate 120 and moved along the perimeter 134 to selectively place the at least one material 144 such that the at least one material 144 is in mechanical contact with the first plate 110 and the second plate 120 along the portion 146 of the perimeter 134. In certain embodiments, the at least one material 144 is applied after forming the polymeric coating, while in certain other embodiments, the at least one material 144 is applied before forming the polymeric coating. The plurality of TE elements 130 in certain embodiments is hermetically sealed at least in part by the at least one material 144 and the polymeric coating.

In certain embodiments, forming the polymeric coating comprises depositing monomers from a monomer gas (e.g., vapor deposition) in the region 132 onto the at least one surface of the first plate 110, the at least one surface of the second plate 120, and the at least one surface of the plurality of TE elements 130, and polymerizing the deposited monomers to form the polymeric coating. For example, the monomer gas can comprise para-xylylene and the polymeric coating can comprise poly(para-xylylene) polymers. In certain such embodiments, the plurality of TE elements 130 is hermetically sealed at least in part by the polymeric coating.

In certain embodiments, the process parameters for depositing the monomers (e.g., pressure, flow rate, and/or temperature of the monomer gas; temperature of the surfaces upon which the monomers are deposited; duration of deposition) can be selected to facilitate deposition of the monomers within the region 132. For example, for a gap between the first plate 110 and the second plate 120 having a gap height in a range between 0.5 millimeter and 3 millimeters and/or having a ratio of the gap height to the plate width of the second plate 120 in a range between 1:20 and 1:30, the process parameters can be selected to have the monomer gas propagate through the gap along the plurality of edges 126 such that the monomers are deposited within at least a predetermined portion of the region 132 (e.g., substantially completely throughout the surfaces within the region 132). In certain embodiments, the thermoelectric device is at room temperature (e.g., in a range between 0° Celsius and 20° Celsius) while the monomer gas is at a temperature higher than the temperature of the thermoelectric device. The process parameters for polymerizing the deposited monomers (e.g., temperature of the surfaces upon which the monomers are deposited; duration of heating of the surfaces) can be selected to facilitate the polymerization. In certain embodiments, the resultant polymeric coating has a thickness in a range between 0.5 micron and 3 microns. In certain embodiments, vapor deposition of the polymeric coating onto the thermoelectric device can be performed without masking of the first plate 110 and/or the second plate 120, which may otherwise be used in a dipping process to protect against excessive deposition of the polymeric coating that would inhibit thermal conductivity between the first plate 110 and the first heat spreader 410 and/or between the second plate 120 and the second heat spreader 420.

In certain embodiments, forming the polymeric coating comprises flowing a liquid polymeric material into the region 132, at least a portion of the liquid polymeric material adhering to the at least one surface of the first plate 110, the at least one surface of the second plate 120, and the at least one surface of the plurality of TE elements 130. For example, flowing the liquid polymeric material into the region can comprise dipping the thermoelectric device into the liquid polymeric material contained within a reservoir, and subsequently removing the thermoelectric device from the reservoir (e.g., once the liquid polymeric material has propagated through the gap along the plurality of edges 126 to be deposited within at least a predetermined portion of the region 132). In certain embodiments, forming the polymeric coating comprises both vapor deposition of a first polymeric material and dipping the thermoelectric device in a second liquid polymeric material.

Discussion of the various embodiments herein has generally followed the embodiments schematically illustrated in the figures. However, it is contemplated that the particular features, structures, or characteristics of any embodiments discussed herein may be combined in any suitable manner in one or more separate embodiments not expressly illustrated or described. In many cases, structures that are described or illustrated as unitary or contiguous can be separated while still performing the function(s) of the unitary structure. In many instances, structures that are described or illustrated as separate can be joined or combined while still performing the function(s) of the separated structures. Various features and aspects of the disclosed embodiments can be combined with or substituted for one another. Any methods disclosed herein need not be performed in the order recited.

The ranges disclosed herein also encompass any and all overlap, sub-ranges, and combinations thereof. Language such as “up to,” “at least,” “greater than,” “less than,” “between,” and the like includes the number recited. With respect to the use of any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. In general, terms used herein are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). If a specific number is intended, such an intent will be explicitly recited in the embodiment, and in the absence of such recitation, no such intent is present.

Various embodiments have been described above. Although the inventions have been described with reference to these specific embodiments, the descriptions are intended to be illustrative and are not intended to be limiting. Various modifications and applications may occur to those skilled in the art without departing from the spirit and scope of the inventions as defined in the appended claims. 

What is claimed is:
 1. A thermoelectric device comprising: a thermally conductive first plate; and at least one thermoelectric sub-assembly comprising: a thermally conductive second plate; a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate, the plurality of thermoelectric elements in thermal communication with the first plate and the second plate; at least one material along at least a portion of a perimeter of the region and mechanically coupled to the first plate and the second plate to provide stiffness to the thermoelectric sub-assembly, the at least one material comprises at least one epoxy, rubber, or silicone; and a hermetic seal comprising at least one polymeric material in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements, the at least one polymeric material comprises poly(para-xylylene) polymers, wherein the hermetic seal comprises the at least one material and the at least one polymeric material.
 2. The thermoelectric device of claim 1, wherein the first plate and the second plate are spaced from one another by a gap having a gap height, the second plate has a planar polygonal shape with a plurality of edges and a plate width between opposing edges of the plurality of edges.
 3. The thermoelectric device of claim 2, wherein the second plate has a rectangular shape with two opposing edges each having a first length and two opposing edges each having a second length less than the first length, the plate width equal to the second length.
 4. The thermoelectric device of claim 2, wherein a ratio of the gap height to the plate width is in a range between 1:20 and 1:30.
 5. The thermoelectric device of claim 1, wherein the at least one polymeric material has a thickness in a range between 0.5 micron and 3 microns.
 6. The thermoelectric device of claim 1, further comprising a first heat spreader in thermal communication with a first surface of the first plate and a second heat spreader in thermal communication with a second surface of the second plate.
 7. The thermoelectric device of claim 6, wherein the first surface is coated by the at least one polymeric material and the second surface is coated by the at least one polymeric material.
 8. A thermoelectric module for thermally conditioning a component, the module comprising: first and second heat spreaders spaced apart from one another and configured to respectively provide cold and hot sides; a thermal insulator material arranged between the first and second heat spreaders; a thermoelectric device operatively engaged with the first and second heat spreaders, the thermoelectric device comprising: a thermally conductive first plate in thermal communication with the first heat spreader; and a plurality of thermoelectric sub-assemblies, each thermoelectric sub-assembly comprising: a thermally conductive second plate in thermal communication with the second heat spreader and having a plurality of edges; a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate, the plurality of thermoelectric elements in thermal communication with the first plate and the second plate; at least one material along at least a portion of the plurality of edges, the at least one material mechanically coupled to the first plate and the second plate; and at least one hermetic seal comprising at least one polymeric material in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements, wherein the at least one hermetic seal comprises the at least one material and the at least one polymeric material, the at least one material different from the at least one polymeric material.
 9. The module of claim 8, wherein, during operation or assembly of the module, the portion experiences a first mechanical force from the second heat spreader and a remaining portion of the plurality of edges experiences a second mechanical force from the second heat spreader, the second mechanical force less than the first mechanical force.
 10. The module of claim 8, wherein the at least one polymeric material comprises poly(para-xylylene) polymers.
 11. The module of claim 8, wherein the second heat spreader is configured to have a fluid coolant flow therethrough.
 12. The module of claim 8, wherein the at least a portion of the plurality of edges along which the at least one material extends is closest to at least one hole in the first plate relative to other portions of the plurality of edges of the region, the at least one hole having a fastener extending therethrough to engage the thermoelectric device to the first and second heat spreaders, the at least one material providing stiffness along the portion of the plurality of the edges closest to the at least one hole with the fastener extending therethrough.
 13. The module of claim 12, wherein an extent of the at least one material along the portion of the plurality of edges is equal to a diameter of the at least one hole.
 14. The module of claim 8, wherein the at least one material comprises a first material and a second material, the first material providing stiffness to the thermoelectric device, the second material relatively less stiff than the first material.
 15. The module of claim 14, wherein the first material is proximate to at least one hole in the first plate relative to the second material, the at least one hole for having a fastener extend therethrough.
 16. The thermoelectric device of claim 1, wherein the at least a portion of the perimeter of the region along which the at least one material extends is closest to at least one hole in the first plate relative to other portions of the perimeter of the region, the at least one hole having a fastener extending therethrough, the at least one material providing stiffness along the portion of the perimeter of the region closest to the at least one hole with the fastener extending therethrough.
 17. The thermoelectric device of claim 16, wherein an extent of the at least one material along the portion of the perimeter of the region is equal to a diameter of the at least one hole.
 18. The thermoelectric device of claim 1, wherein the at least one material comprises a first material and a second material, the first material providing stiffness to the thermoelectric sub-assembly, the second material relatively less stiff than the first material.
 19. The thermoelectric device of claim 18, wherein the first material is proximate to at least one hole in the first plate relative to the second material, the at least one hole for having a fastener extend therethrough.
 20. A thermoelectric device comprising: a thermally conductive first plate; and at least one thermoelectric sub-assembly comprising: a thermally conductive second plate; a plurality of thermoelectric elements in a region bounded by and including the first plate and the second plate, the plurality of thermoelectric elements in thermal communication with the first plate and the second plate; at least one material along at least a portion of a perimeter of the region and mechanically coupled to the first plate and the second plate to provide stiffness to the thermoelectric sub-assembly; and a hermetic seal comprising at least one polymeric material in the region on at least one surface of the first plate, at least one surface of the second plate, and at least one surface of the plurality of thermoelectric elements, the at least one polymeric material comprises poly(para-xylylene) polymers, wherein the hermetic seal comprises the at least one material and the at least one polymeric material, the at least one material different from the at least one polymeric material.
 21. The thermoelectric device of claim 20, wherein the first plate and the second plate are spaced from one another by a gap having a gap height, the second plate has a planar polygonal shape with a plurality of edges and a plate width between opposing edges of the plurality of edges, wherein a ratio of the gap height to the plate width is in a range between 1:20 and 1:30.
 22. The thermoelectric device of claim 20, further comprising a first heat spreader in thermal communication with a first surface of the first plate and a second heat spreader in thermal communication with a second surface of the second plate.
 23. The thermoelectric device of claim 20, wherein the at least a portion of the perimeter of the region along which the at least one material extends is closest to at least one hole in the first plate relative to other portions of the perimeter of the region, the at least one hole having a fastener extending therethrough, the at least one material providing stiffness along the portion of the perimeter of the region closest to the at least one hole with the fastener extending therethrough.
 24. The thermoelectric device of claim 23, wherein an extent of the at least one material along the portion of the perimeter of the region is equal to a diameter of the at least one hole.
 25. The thermoelectric device of claim 20, wherein the at least one material comprises a first material and a second material, the first material providing stiffness to the thermoelectric sub-assembly, the second material relatively less stiff than the first material.
 26. The thermoelectric device of claim 25, wherein the first material is proximate to at least one hole in the first plate relative to the second material, the at least one hole for having a fastener extend therethrough. 